A sex position is a position of the body that people use for sexual intercourse or other sexual activities. Sexual acts are generally described by the positions the participants adopt in order to perform those acts. Though sexual intercourse generally involves penetration of the body of one person by another, sex positions commonly involve penetrative or non-penetrative sexual activities. Three categories of sexual intercourse are commonly practiced: vaginal intercourse involving vaginal penetration , anal penetration , and oral sex especially mouth-on-genital stimulation. The act may also involve anilingus.
Woman on top is any sex position in which the woman is on top of her sexual partner during sexual activity. The position most commonly associated with the woman on top is often called the cowgirl or riding position, which derives its name from the image of the woman "riding" the man as a cowgirl rides a bucking horse. In that position, a man typically lies on his back with his legs closed, while the female partner straddles him, usually in a kneeling position facing either forward or back, and either the man or woman inserts the man's erect penis into the woman's vagina or anus.